Are there signs of impending breakdown?

Short Answer:
Unusual motor noises and erratic operating behavior are the most common
symptoms of vibrator malfunction, although many simply quit working without
warning.

Long Answer: Many vibrators
will just quit working one day for no apparent reason. You flip the
switch and...nothing. Even fresh batteries will fail to revive it. If it
does whir back to life after a few whacks or shakes, consider yourself
warned that it may be on the way out. Erratic behavior, stopping and
starting for no apparent reason, and failure to respond correctly to the
controls are all signs that something is amiss with your vibe. Rattling
in the motor or other unusual noises can also signal an immanent
vibrator breakdown. If the motor heats up, or produces an acrid or
burning odor, these are also signs that your vibe may be breaking down
or wearing out.

In multispeed or multifunction vibrators,
or vibrators with more than one vibrating component, one motor may quit
working independently of the other, or the vibrator may get stuck on one
speed. Although the vibrator may continue to operate well otherwise, you'd do well to keep an eye on it for other malfunctions.

If your vibrator is
rattling or making a strange noise, or if the motor is overheating or
smells like it's burning, you should put it to rest. If it's under
warranty, you may be able to get it replaced by the manufacturer.
Otherwise it's time to start shopping for your next toy.